Posted: Apr 21, 2013 2:47 PM by CBS News
Investigators believe that two brothers suspected in the Boston Marathon bombing were likely planning other attacks based on the cache of weapons uncovered, the city's police commissioner told CBS' "Face the Nation" on Sunday.
Boston Police Commissioner Ed Davis told "Face the Nation" host Bob Schieffer that authorities found an arsenal of homemade explosives after Friday's gun battle between police and the two suspects.
"We have reason to believe, based upon the evidence that was found at that scene - the explosions, the explosive ordnance that was unexploded and the firepower that they had - that they were going to attack other individuals," Davis said. "That's my belief at this point."
The scene of the gun battle was loaded with unexploded bombs, and authorities had to alert arriving officers to them and clear the scene, Davis said. One improvised explosive device was found in the Mercedes the brothers are accused of carjacking, he said.
"This was as dangerous as it gets in urban policing," Davis said.
"In a case when there are exigent circumstances -- public safety is involved," explained CBS News senior correspondent John Miller, the government can invoke the exception to determine, "Are there other explosives? Is there another plot to blow something up? Are there other people?"
Massachusetts Gov. Deval Patrick said Sunday that surveillance video from Monday's Boston Marathon attack shows Dzhokhar Tsarnaev dropping his backpack and calmly walking away from it before the bomb inside it exploded.
Patrick also said that he has no idea what motivated the suspects. Speaking on CBS' "Face the Nation," Patrick said it's hard to imagine why someone would deliberately harm "innocent men, women and children in the way that these two fellows did."
Patrick also said law enforcers believe the immediate threat ended when police killed one suspect and captured the other.
According to an FBI news release, a foreign government said that Tamerlan Tsarnaev appeared to be a strong believer and that he had changed drastically since 2010 as he prepared to leave the U.S. for travel to a region in Russia to join unspecified underground groups.
The FBI did not name the foreign government, but the two officials said it was Russia. The officials spoke on condition of anonymity because they were not authorized to talk about the matter publicly.